Texturing Fractured Objects
I would suggest using Scorpion 81's fracture modifier build instead of Blender's default cell fracture. There, the fracture is a modifier, so you can unwrap and apply your material to a cube, and after fracturing each piece of the fracture will retain it's original uv coordinates. In addition, Scorpion 81's fracture modifier build offers some great features for streamlining and making easier the fracturing process.

Here is a link to an example of the modifier in action:
https://www.youtube.com/watch?v=6Vcd1GQw5Ac

Here is the fracture modifier build's page:
http://df-vfx.de/fracturemodifier/